Frequency specificity of 80-Hz amplitude-modulation following response

Abstract

The usefulness of 80-Hz amplitude-modulation following response (AMFR) detected by phase coherence to predict the hearing threshold during sleep was evaluated in 90 ears of 53 children with hearing impairment. The threshold of 80-Hz AMFR at carrier frequency of 1,000 Hz and the threshold of auditory brainstem response (ABR) elicited by 1,000 Hz tone pips in children during sleep were compared with behavioral hearing threshold, which was determined by standard pure-tone audiometry or play audiometry. In 12 ears of 12 children with various patterns of hearing impairment, 80-Hz AMFR at different carrier frequencies were examined, and the threshold pattern was compared with the pure-tone audiogram to investigate the frequency specificity of 80-Hz AMFR detected by phase coherence. The mean and standard deviation of the difference between 80-Hz AMFR and pure-tone thresholds was 4.3 and 12.1 dB, respectively, and that between ABR and pure-tone thresholds was 6.6 and 14.2 dB, respectively. The threshold patterns of 80-Hz AMFR very closely resembled the corresponding audiogram patterns in all types of hearing impairment. The measurement of 80-Hz AMFR in children during sleep thus appeared to be more accurate in hearing prediction than that by ABR elicited with tone pips and to have a good frequency specificity.